The therapeutic use of thermal blankets having walls of flexible polymeric material that are sealed together to define a labyrinth of passages for the circulation of heating or cooling fluid is well known. While such therapy may involve either heating or cooling portions of the body, it is the cooling mode that in recent years has received particular attention because of its effectiveness in post-operative treatment and in connection with physical therapy. In particular, cryotherapy following soft tissue trauma has been shown to reduce pain, swelling blood loss, inflammation and hematoma formation. During the rehabilitative process, cryotherapy has been utilized effectively to diminish inflammation and patient discomfort.
For such therapy, the thermal blanket should fit snugly about and uniformly contact the area of the body requiring treatment. Where the treatment site is relatively flat, or is of regular contour, these objectives may be accomplished with a blanket that normally lies flat and can be placed against, or wrapped about, the body part. However, such objectives are far more difficult to achieve when a body portion to receive thermal treatment is a joint area of complex and variable curvatures such as the ankle and foot.
The problems of providing effective cryotherapy (or heat therapy) to such a joint area using a blanket having fluid circulation passages are further complicated by the difficulties of insuring proper flow throughout the blanket when it has been folded or wrapped about the treatment site. If, for example, the blanket is of a type that allows thermal fluid to flow at random because the thermoplastic layers are joined together at a multiplicity of points that do not provide clearly-defined flow routes, then, when such a blanket is wrapped or folded about the treatment site, the thermal fluid can be expected to take paths of least resistance and certain areas of the blanket may receive little or no fluid circulation. On the other hand, if the blanket is of a type that has clearly defined (i.e., tubular) flow passages, there is a risk that such passages may become kinked and obstruct fluid flow when the blanket is folded or wrapped about the treatment site.
All such blankets that provide for the circulation of thermal fluid have inlet and outlet tubes leading to and from the cooling/heating/pumping equipment that controls fluid temperature and directs flow circulation. Such tubes, and the inlet and outlet passages of the blanket with which they communicate, are vulnerable to kinking and twisting that might result in flow obstruction as the patient moves about or changes body position during waking hours and in particular, during sleep, when such obstruction of the passages may go unnoticed.
Accordingly, an important aspect of this invention lies in providing a blanket that is particularly suitable for thermal treatment of the ankle and foot and may be easily adjusted to fit patients of different size and physical characteristics notwithstanding the fact that the blanket is manufactured in substantially flat or planar condition. A zigzag arrangement of dual passages extends through the blanket in directions that eliminate or greatly reduce possibilities of partial or total flow obstruction since, by reason of such arrangement, forces imposed on the passages when the blanket is properly wrapped about the foot and ankle tend to be in the form of twisting rather than kinking forces. Kinking of inlet and outlet tubes and the inlet/outlet passages of the blanket with which they communicate is prevented by providing the blanket with an integral leg wrap that supports the tubes and the fluid coupling element(s) connected to them and immobilizes such tubes and element(s) in relation to the patient's leg. Close fitting of the blanket to the treatment site is assured by providing the blanket with an outline of distinctive and developed shape in which certain sections are connected by one or more elastic webs, by utilizing Velcro-type hook and loop attachment means, and by providing substantially the entire outer (exterior) panel of the blanket with a soft loop-providing pile fabric which constitutes the loop component of the hook-loop attachment system.
Briefly, the foot and ankle blanket is composed of inner and outer panels of easily foldable material having an outline defining two foot sections (lateral and medial) and an ankle section integral therewith. The outer panel has its entire outer surface formed of soft loop pile fabric and the inner panel is composed of double layers of thermoplastic sheet material heat-sealed together to define at least one (most advantageously two) serpentine flow passage(s) extending along a zigzag pathway from an inlet opening to an adjacent outlet opening. The foot sections have bottom edges joined by at least one (preferably two) two-way stretch elastic web(s) positioned to underlie a patient's foot and extend behind the heel when the blanket is worn. A T-shaped leg wrap is formed integrally with the ankle section and includes an upwardly-extending strap portion which contains the inlet and outlet tubes for the blanket. At its top, the T-shaped section includes a band portion that wraps about the lower portion of the wearer's leg and attaches to itself to maintain the inlet-outlet tubes in untwisted and unkinked condition. Velcro-type hook patches are provided by one of the foot sections, the ankle section, and the strap portion of the T-shaped section, for holding the blanket in snug, slightly tensioned, and elastically conformable condition about a wearer's foot and ankle, thereby insuring effective thermal treatment when the blanket is in use.
Other features, objects, and advantages will become apparent from the specification and drawings.